Air ionizer



Feb. 8, 1966 A. STREIB 3,

AIR IONIZER Filed Dec. 28, 1961 llnitecl States Patent ice 3,234,432 AIRIONIZER Albrecht Streib, Princeton, N..l., assignor to Radio Corporationof America, a corporation of Delaware Filed Dec. 28, 1961, Ser. No.162,784 7 Claims. (Cl. 317-4) This invention relates generally to airionizers, and more particularly to anion producing device adapted toprovide a relatively steady stream of unipolar ions in a desireddirection. The apparatus of the present invention is particularly usefulfor producing a controlled stream of unipolar ions toward a livingsubject for therapeutic and/or research purposes.

It has been proposed to subject apatient, for example, to ions byinjecting the ion-s into the air and then blowing the ionized air in thegeneral direction of a patient. This method of producing a stream ofions is objectionable because it subjects the patient to air drafts thatmay be harmful to'him. It has also been proposed to produce ionized airby stretching a pair of fine wires across a room and applying apotential to them to produce an ion discharge between them and surfacesof the room. This method of ion production is not quite satisfactorybecause a large number of the ions produced travel to the nearby ceilingand walls where the ions are lost. The potential necessary to produceions by this method is excessive, and it may produce an objectionableamount of ozone, oxides of nitrogen, and possibly peroxides,productsthat are considered harmful in large concentrations.

It has been proposed further to use a grounded metal sheet electrode anda fine wire electrode as an ion-producing device. This meansforproducing ions also leaves something to be desired because it wasfound that the ion current to the grounded metal sheet was excessive fordesired ion concentrations and tended to increase the probability of theaforementioned undesired products. It was also found that, when themetal sheet was grounded, the ion densities at the patients location didnot vary proportionately withthe potentials applied between theelectrodes, but the ion densities tended to fluctuate mark- It is anobject of the present invention to provide im: proved means forproducing a relatively steady stream of ions without producingobjectionable drafts.

.Another object of the present invention is to provide an improved ionproducing deviceforproviding a steady stream of unipolar ions withoutproducing objectionable quantities of ozone, oxides, and peroxides. r i

. Still another object of the present invention'is to provide improvedion producing means whose threshold potential for initiating aflow ofions in the air is a minimum and whose current requirements are aminimum for a desired ion density. a

A further object of the present invention is to provide improved ionproducing means whose output of ions may be easily controlled. 4 I

Still a further object of the present invention is to provide animproved ion producing device of the type described that is relativelysimple in structure, easy to operate, and highly efficient in use.

Briefly, the ion producing device of thepresent invention comprises twoelectrodes, a shieldelectrod'eand a Wire electrode. Potentials ofopposite polarity from a voltage source are applied to the electrodesthrough a shielded cable. One end of the shielding conductor of theshielded cable is grounded adjacent to one output terminal of thevoltage source. The other end of the shielding conductor is connected tothe shield electrode through a resistor whose resistance is at least onemegohm. The other output terminal of the voltage source is connected tothe wire electrode through a series circuit comprising the innerconductor of the shielded cable and a current limiting re sistor, thelatter usually being a part of the voltage source. With thisarrangement, the threshold potential at which ion current is produced isa minimum, and the current required to retain a desired ion density at aremote point from the electrodes is nearly a minimum also. The resistorconnected to the shield electrode provides a small steady controlledleakage of ions to ground and causes the ion producing device to emit asteady stream of Referring, now, to the drawing, there is shown an airionizer 10 employing an ion-producing device in the form of an ionreflector 12. The ion reflector 21 comprises an elongated shieldelectrode 14 of metal, such as aluminum, steel, or metallized insulatingmaterial. The shield electrode 14 is formed with a central panel 16 anddownwardly extending side panels 18 and 20, as viewed in the drawing. Apair of spaced-apart eyelets 22 and 24 are fixed to the panel 16 forretaining the ends of cords 26 and 28, respectively, therein. The cords26 and 28, from which the panel 16 is suspended, are disposed overpulleys 30 and 32, respectively, for raising and lowering the shieldelectrode 14 to a desired position in space.

A wire electrode 34 is depended from the central panel 16 by a pair ofinsulators 36 and 38. The wire electrode 34 lies substantially in theplane defined by the lower edges of the side panels 18 and 20. Theinsulators 36 and 38 may be capped with metal balls 40 and 42, connectedto and terminating the ends of the wire 34, to prevent a coronadischarge from the ends of the wit electrode 34. V

Means are provided to supply a unidirectional potential between theshield electrode 14 and the wire electrode 34 to causeions to flowtherebetween. To this end, there is provided a D.-C. (direct current)power supply 44 adapted to supply a unidirectional voltage betweenpositive and negative output terminals 46 and 48, respectively.

The power supply 44 comprises an A.-C. input control device 50 having apair of input terminals 52 and 54 adapted to be connected to anysuitable source of A.-C. (alternating current) voltage. The controldevice 50 comprises a variable auto transformer whose variable output isapplied to the input of the power supply 44 for controlling the voltageand current output of the latter in any suitable manner known in theart. The positive a terminal 46 of the power supply is connected toacornmon a power supply 44 to the electrodes 14 and 34 of the ionPatented Feb..8, 1966,

reflector 12. The cable 58 comprises a shielding conductor 60 and aninner conductor 62. One end of the inner conductor 62 is connected tothe negative terminal 48 of the power supply through a protectiveresistor 64. The other end of the inner conductor 62 is connecteddirectly to the wire electrode 34. The resistor 64, shown schematicallyas being outside of the power supply 44, is usually incorporated withinthe power supply 44, and serves to limit the current output of the powersupply so as to prevent injuriously shocking a person who mayaccidentally come in contact with a portion of the circuit connected tothepower supply. 7

The end of the shielding conductor 60 that is adjacent to the powersupply 44 is connected to ground, and the end of the shielding conductor60 adjacent to the shield electrode 14 is connected to the shieldelectrode 14 through a resistor 66; Depending upon the geometry and thedimensions of the ion reflector 12, the resistor 66 should have a valueof resistance of between one and 1,000 megohms. The resistor 66 servesas means to ground the shield electrode 14 when a voltage is firstapplied between the electrodes 14 and 34, and provides a path ofcontrolled leakage of ions during normal operation. It is the controlledleakage provided by the resistor 66 that prevents unwanted charges fromremaining on :the shield electrode when the power supply potential andcurrent are adjusted downward, thus providing a relatively proportionalflow of ions to the shield electrode 14, and an easily controlled flowof ions for application to a subject.

In order to produce a steady stream of negative ions, in a downwarddirection, looking at the drawing, the power supply 44 is connected tothe ion reflector 12 in the manner illustrated in the drawing. The inputterminals 2 and 54 of the power supply are connected to a suitablesource of A.-C. voltage, and the control device 50 is varied until adischarge of negative ions from the electrode 34 is initiated. It isapparent that, in the absence of a flow of ions between the electrodes34 and 14, the shielded electrode 14 is at ground potential. After theflow of ions between the electrodes 34 and 14 has been initiated, avoltage drop occurs across the resistor 66 that varies with the currentsupplied by the power supply 44, a function of the voltage appliedbetween the electrodes 34 and 14. Thus, the potential at the shieldelectrode 14 becomes negative with respect to ground as the ion currentbetween the electrodes 34 and 14 increases with the polarity ofconnections shown. During this process, negative ions travel, inrelatively small numbers, not only from the wire electrode 34 toward theshield electrode 14 but travel, in far greater numbers, away from theshield electrode 14 in a relatively steady stream, in

a downward direction, looking at the drawing.

With thecircuitr-y shown in the drawing, the shield electrode 14functions as an artificial ceiling with respect to thewire electrode 34.It vis thus possible to raise or lower the ion reflector 12 to anyposition over a patient, for example, without having the walls andceiling of the room interfere variably with the stream of ions reachingthe patient. Without the controlled leakage provided by the resistor 66,the shield electrode 14 would become excessively charged periodicallyand would discharge periodically, thereby causing the stream of ions inthe direction of a patient to vary excessively.

In order to producea stream of positive ions from the electrode 34, itis only necessary to reverse the polarity of the power supply so thatthe terminal 48 is positive and the terminal 46 is negative.

From the foregoing description, it will be apparent that there has beenprovided an improved air ionizer employing an improved ion-producingdevice that utilizes a minimum potential to initiate an ion dischargeand utilizes a minimum potential to maintain a desired steady stream ofions. Whilethe improved apparatus of this invention has been shown indiagrammatic form, various components useful therein, as well asvariations in the apparatus itself, coming within the spirit of thisinvention will, no doubt, readily suggested themselves to those skilledin the art. Hence, it is desired that the foregoing shall be consideredmerely as illustrative and not in a limiting sense.

What is claimed is:

1. In apparatus of the type wherein a voltage is to be applied betweentwo electrodes to cause ions to flow therebetween, one of saidelectrodes comprising a metal shield, the other of said electrodescomprising a wire spaced and insulated from said shield, the improvementcomprising a shielded cable including an inner conductor and a groundedshielding conductor for conducting current to said electrodes, meansconnecting said inner conductor to said wire, a resistor, and meansconnecting said resistor between said shield and said shieldingconductor whereby ions travel in a relatively steady stream away fromsaid metal shield.

2. In apparatus of the type wherein a voltage from a unidirectionalvoltage source is to be applied between two electrodes to cause ions toflow therebetween, one of said electrodes comprising a metal shield, theother of said electrodes comprising a wire spaced and insulated fromsaid shield, the improvement comprising a shielded cable including aninner conductor and a grounded shielding conductor therefor, means forconnecting one end of said shielding conductor to one terminal of saidvoltage source, means for connecting another terminal of said voltagesource to said wire through said inner conductor, a resistor having aresistance within a range of 1 to 1,000 megohms, and means connectingsaid resistor between said shielding conductor and said shield wherebyions travel in a relatively steady stream away from said metal shield.

3. Apparatus comprising a metal shield electrode, a wire spaced fromsaid metal shield and insulated therefrom, a shielded cable comprisingan inner conductor and a grounded shielding conductor therefor, mean-sconnecting said inner conduct-or to said wire, a resistor, and meansconnecting said shielding conductor .to said metal shield through saidresistor whereby ions travel in a relatively steady stream away fromsaid metal shield.

4. Apparatus comprising a metal shield electrode, a wire spaced fromsaid metal shield and insulated therefrom, a shielded cable comprisingan inner conductor and a grounded shielding conductor therefor, saidinner conductor being connected to said Wire, a resistor having a valueof resistance between 1 megohm and 1,000 megohm-s, and means connectingsaid shielding conductor to said metal shield through said resistor.whereby ions travel in a relatively steady stream away from said metalshield.

5. Apparatus comprising an elongated shield electrode having oppositeedgesextending to one side of said shield to act as areflector, a wireelectrode spaced from said shield electrode and insulated therefrom,means to apply a unidirectional potential to said electrodes through ashielded cable, said cable comprising a first conductor and a groundedsecond conductor adapted to shield said first conductor, a resistor,means connecting said first conductor to said wire electrode, and meansconnecting said second conductor to said shield electrode through saidresistor whereby ions travel in a relatively steady stream away fromsaid shield electrode.

6. Apparatus comprising an elongated metal shield electrode havingopposite side portions extending to one side of said shield electrode tofunction as a reflector, a wire electrode spaced from said shieldelectrode and insulated therefrom, means to apply a unidirectionalpotential between said electrodes through a shielded cable, said cablecomprising afirst conductor and a grounded second conductor adapted toshield said first conductor, a resistor having a value of a resistanceof at least one megohm, means connecting said first conductor to saidwire electrode, and means connecting said second conductor to saidshield electrode through said resistor whereby ions travel in arelatively steady stream away from said shield electrode.

7. An ion reflector comprising a metal shield, insulat- 'ing means, awire electrode spaced from said metal shield by said insulating means, aresistor having a value of resistance within the range of 1 to 1,000megohms, one end of said resistor being connected to said metal shieldand another end of said resistor being adapted to be connected toground, means to apply a source of voltage between ground and said wireelectrode, and means connected to said metal shield to adjust theposition of said ion reflector in space whereby said metal shield actsas an artificial ceiling with respect to said wire electrode.

References Cited by the Examiner UNITED STATES PATENTS SAMUEL BERNSTEIN,Primary Examiner.

MAX L. LEVY, Examiner.

1. IN APPARATUS OF THE TYPE WHEREIN A VOLTAGE IS TO BE APPLIED BETWEENTWO ELECTRODES TO CAUSE IONS TO FLOW THEREBETWEEN, ONE OF SAIDELECTRODES COMPRISING A METAL SHIELD, THE OTHER OF SAID ELECTRODESCOMPRISING A WIRE SPACED AND INSULATED FROM SAID SHIELD, THE IMPROVEMENTCOMPRISING A SHIELDED CABLE INCLUDING AN INNER CONDUCTOR AND A GROUNDEDSHIELDING CONDUCTOR FOR CONDUCTING CURRENT TO SAID ELECTRODES, MEANSCONNECTING SAID INNER CONDUCTOR TO SAID WIRE, A RESISTOR, AND MEANSCONNECTING SAID RESISTOR BETWEEN SAID SHIELD AND SAID SHIELDINGCONDUCTOR WHEREBY IONS TRAVEL IN A RELATIVELY STEADY STREAM AWAY FROMSAID METAL SHIELD.